Honestly how  many years is it now 4-5?  And master and Guru still don´t have like this goal reward you get like when you hit pro or artisan.   I mean the rewards does not need to the special like maybe a +1 or 2 silver clothing and some thing else.  Say you get master cocking one silver cloth armor +1 and 50 lion meat or somethign.  Like a little reward for reaching the goal.   I mean they have it for the other ranks so. 

Someone on Discord made the same suggestion quite recently.
One could argue that at the point you reached Master or even Guru, you don't really need rewards anymore as you should probably already have an abundance of materials and good enough clothing at that point. But it's just a little something either way. Heck even a gold bar reward is at least something.